Thrust vector control

ABSTRACT

A thrust vector control system for a flight vehicle comprises a fixed nozzle defining a first thrust vector direction and at least one exhaust deflector moveable to a location downstream of said fixed nozzle to provide a second thrust vector direction. Movement of the at least one exhaust deflector may allow for simultaneous control of both thrust vector direction and nozzle throat area. Translational motion of each exhaust deflector may be independently controlled. A flight vehicle incorporating a thrust vector control apparatus, and a method for thrust vector control are also disclosed.

BACKGROUND OF THE INVENTION

The present invention relates generally to apparatus and methods forthrust vector control, and more particularly to thrust vector controlfor a gas turbine engine of a flight vehicle.

Gas turbine engines for modern military and commercial aircraft useexhaust nozzles to control engine exhaust expansion and velocitydistribution. By controlling engine exhaust expansion and velocitydistribution, the engine exhaust nozzle provides relatively high thrustefficiency.

Conventional control of the discharge of the heated exhaust gas from agas turbine engine may be achieved by varying the throat area of thenozzle. The throat area is defined as the minimum area through which theheated gas must pass to be discharged from the nozzle exit. For aconvergent nozzle, the nozzle throat is typically the nozzle exit.

Prior art mechanisms for throat area control of an exhaust nozzle of agas turbine engine are disclosed, for example, in U.S. Pat. No.3,519,207 to Clough, and U.S. Pat. No. 3,837,577 to Perez Jr. However,neither the '207 nor the '577 teach a mechanism or method for control ofthrust vector direction.

It is known in the art that thrust vector control may provide improvedflight control to aircraft. Prior art thrust control systems forchanging the nozzle convergent-divergent flow path are heavy andexpensive, and require complex control mechanisms. For example, U.S.Pat. No. 6,369,527 to Feder et al. discloses a swivelingconverging-diverging nozzle comprising a plurality of diverging flapsand converging flaps, wherein the converging flaps comprise alternatingdriven converging flaps and follower diverging flaps.

Fluidic nozzles have also been designed in the prior art, in an attemptto achieve thrust vector control, in which engine compressor bleed airhas been injected into the nozzle flow path to deflect exhaust gas. Suchfluidic nozzles require expensive piping systems to inject the bleed airinto the nozzle exhaust gas flow. In addition, such fluidic designs areinefficient, difficult to control, and particularly unsuitable for lowengine power applications, such as idle conditions.

As can be seen, there is a need for a system and method for thrustvector control of a flight vehicle, wherein the thrust vector controlsystem has a relatively simple mechanical design, and yet effectivelycontrols thrust vector direction, and provides smooth flight controlover a broad range of engine power conditions.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a thrust vector control systemcomprises a fixed nozzle; and at least one exhaust deflector adapted formovement to a location downstream of the fixed nozzle, wherein themovement comprises translational motion, and the movement of eachexhaust deflector is independently controllable.

In another aspect of the present invention, a thrust vector controlsystem comprises a fixed nozzle having a fixed nozzle axis and a fixednozzle exit, wherein the fixed nozzle axis defines a first thrust vectordirection; and a single exhaust deflector is adapted for movement to alocation downstream of the fixed nozzle exit to provide a second thrustvector direction.

In yet another aspect of the present invention, a thrust vector controlsystem comprises a fixed nozzle for a gas turbine engine, the fixednozzle having a fixed nozzle exit; and a thrust vector control apparatusincluding at least one exhaust deflector, each exhaust deflector adaptedfor independent translational motion, or a combination of translationaland rotational motion, to a location downstream of the fixed nozzleexit, wherein the fixed nozzle provides a first thrust vector direction;and each exhaust deflector is adapted for converting the first thrustvector direction to a second thrust vector direction.

In still another aspect of the present invention, there is provided asystem comprising a gas turbine engine having a fixed nozzle fordischarging exhaust gas; at least one exhaust deflector, each exhaustdeflector independently capable of changing a first thrust vector of thegas turbine engine, wherein each exhaust deflector is adapted formovement to a location downstream of the fixed nozzle; and an actuatoradapted for actuating movement of each exhaust deflector, wherein themovement of each exhaust deflector is independently controllable, andthe movement of each exhaust deflector comprises translational motion.

In a further aspect of the present invention, a thrust vector controlapparatus comprises at least one deflection unit, each deflection unitincluding an exhaust deflector adapted for movement to a locationdownstream of a fixed nozzle of a gas turbine engine, wherein the fixednozzle has a fixed nozzle axis; and an actuator in communication withthe exhaust deflector, the actuator for actuating movement of eachdeflection unit, wherein the fixed nozzle provides a first thrust vectordirection substantially parallel to the fixed nozzle axis, the movementof each exhaust deflector to the location downstream of the fixed nozzlecomprises translational motion, and the movement of each exhaustdeflector to the location downstream of the fixed nozzle provides asecond thrust vector direction at a thrust vector angle, α to the fixednozzle axis.

In yet a further aspect of the present invention, a flight vehiclecomprises a gas turbine engine having a fixed nozzle; and a thrustvector control apparatus for controlling a thrust vector of the gasturbine engine, wherein the thrust vector control apparatus comprises atleast one exhaust deflector, each exhaust deflector is independentlycontrollable, and each exhaust deflector is movable with respect to afixed nozzle exit of the fixed nozzle.

In still a further aspect of the present invention, a method for thrustvector control of a flight vehicle, comprises passing exhaust gas from afixed nozzle of a gas turbine engine, the fixed nozzle having a fixednozzle axis defining a first thrust vector direction; and moving atleast one exhaust deflector to a location downstream of the fixed nozzleto provide a second thrust vector direction.

In yet another aspect of the present invention, a method for thrustvector control of a flight vehicle comprises providing a thrust vectorcontrol apparatus for the flight vehicle, wherein the flight vehicleincludes a gas turbine engine having a fixed nozzle, the fixed nozzlehaving a fixed nozzle axis defining a first thrust vector directionsubstantially parallel to the fixed nozzle axis, and wherein the thrustvector control apparatus comprises at least one exhaust deflector. Themethod further comprises passing exhaust gas from the fixed nozzle, andmoving the at least one exhaust deflector with respect to the fixednozzle to provide a second thrust vector angle, α to the fixed nozzleaxis, wherein moving the at least one exhaust deflector with respect tothe fixed nozzle comprises translational motion of the at least oneexhaust deflector to a location downstream of the fixed nozzle.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdrawings, description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically representing a flight vehicleincorporating a thrust vector control apparatus, according to theinstant invention;

FIG. 2 is a block diagram schematically representing a thrust vectorcontrol system, according to the invention;

FIG. 3 is a block diagram schematically representing a thrust vectorcontrol apparatus, according to the invention;

FIGS. 4A-C each show a configuration of a deflection unit for a thrustvector control apparatus, according to the invention;

FIG. 5A is a side view schematic representation of a thrust vectorcontrol system having both a first exhaust deflector and a secondexhaust deflector in a retracted position, according to the invention;

FIG. 5B is a side view schematic representation of a thrust vectorcontrol system having both a first exhaust deflector and a secondexhaust deflector in an extended position, according to the invention;

FIG. 5C is a side view schematic representation of a thrust vectorcontrol system having a first exhaust deflector in an extended position,and a second exhaust deflector in a retracted position, according to theinvention;

FIG. 5D is a side view schematic representation of a thrust vectorcontrol system having a first exhaust deflector in a retracted position,and a second exhaust deflector in an extended position, according to theinvention;

FIG. 6 is a lateral cross-sectional view schematically representing aflight vehicle indicating a pitch plane and a yaw plane;

FIG. 7A schematically represents a series of steps involved in a methodfor thrust vector control of a flight vehicle, according to theinvention; and

FIG. 7B schematically represents a series of steps involved in a methodfor thrust vector control of a flight vehicle, according to anotherembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out the invention. The description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention, since the scope of theinvention is best defined by the appended claims.

Broadly, the present invention provides apparatus and methods for thrustvector control of a nozzle of a flight vehicle. The present inventionmay be used to change, or control, the thrust vector direction of, forexample, a gas turbine engine. The present invention may also allow forsimultaneous control of nozzle throat area and thrust vector direction.The present invention may be used for flight control of aircraft,including rotorcraft and fixed-wing aircraft, as well asrocket-propelled space vehicles, missiles, and the like. The presentinvention may also be used for flight control of tailless flightvehicles and unmanned flight vehicles.

In contrast to prior art fluidic nozzles, which inject bleed air intothe nozzle flow path, and swiveling converging-diverging nozzles havinga plurality of diverging flaps and converging flaps, the presentinvention comprises a fixed nozzle and one or more exhaust deflectorsfor movement by translational motion, or a combination of translationaland rotational motion, to a location downstream of the fixed nozzleexit. In further contrast to prior art nozzles, which require pipingsystems for diverting bleed air to the nozzle, or the coordinatedmovement of several nozzle flaps simultaneously, the present inventionmay provide thrust vector control by movement of a single exhaustdeflector, or alternatively by movement of at least one pair of exhaustdeflectors, with respect to a fixed nozzle, wherein movement of eachexhaust deflector may be independently controlled.

FIG. 1 is a block diagram schematically representing a flight vehicle10, according to one aspect of the instant invention. Flight vehicle 10may include one or more gas turbine engines 20. Gas turbine engine(s) 20may comprise a conventional propulsion gas turbine engine for propulsionof flight vehicle 10. Each gas turbine engine 20 may have a fixed nozzle30 for discharge of exhaust gases therefrom, thereby providing thrustfor propulsion of flight vehicle 10. Fixed nozzle 30 may have a fixednozzle axis 31 and a fixed nozzle exit 32 (see, for example, FIGS.5A-D). Flight vehicle 10 may further include a thrust vector controlapparatus 40, which may be adapted for use in conjunction with fixednozzle 30.

Thrust vector control apparatus 40 may be used to change or controlthrust vector direction of gas turbine engine 20. Flight vehicle 10 maybe, for example, an aircraft, such as a rotorcraft or a fixed-wingaircraft, or a rocket-propelled space vehicle, a missile, or the like.Flight vehicle 10 may also be a tailless flight vehicle. Flight vehicle10 may also be an unmanned flight vehicle (UAV). Thrust vector controlapparatus 40 may have additional features and elements as describedhereinbelow, for example, with reference to FIG. 3.

FIG. 2 is a block diagram schematically representing a thrust vectorcontrol system 100, according to one aspect of the invention. Thrustvector control system 100 may include a thrust vector control apparatus40 adapted for use in conjunction with fixed nozzle 30, as describedherein with reference to, e.g., FIGS. 1, 3, and 5A-D. Thrust vectorcontrol system 100 may include a controller 110 in communication withthrust vector control apparatus 40, wherein controller 40 may be adaptedfor controlling thrust vector control apparatus 40. As a non-limitingexample, controller 40 may comprise a flight controller, such as aDigital Electronic Engine Control (DEEC) adapted for automated enginepower management, or a Fully Automated Digital Electronic Control(FADEC). Such flight controllers are well known in the art.

FIG. 3 is a block diagram schematically representing a thrust vectorcontrol apparatus 40, according to the invention. Thrust vector controlapparatus 40 may include one or more deflection units 60. Each gasturbine engine 20, and each fixed nozzle 30, may have one or a pluralityof deflection units 60 for use in conjunction therewith. As an example,each deflection unit 60 may have one (1), two (2), or four (4)deflection units 60 for use in conjunction with each gas turbine engine20/fixed nozzle 30.

Again with reference to FIG. 3, each deflection unit 60 may include anactuator 70, and an exhaust deflector 90 coupled to actuator 70.Deflection unit 60 may further include a linkage unit 80 for couplingexhaust deflector 90 to actuator 70. Deflection unit 60, includingactuator 70, linkage unit 80, and exhaust deflector 90, may be housedradially outward from fixed nozzle 30 (see, e.g., FIGS. 5A-D). Inalternative embodiments (not shown), deflection unit 60 may be at leastpartly disposed within fixed nozzle 30.

Each actuator 70 may be in signal, hydraulic, or electro-mechanicalcommunication with controller 110 and linkage unit 80 for controllingmovement of each exhaust deflector 90, wherein movement of each exhaustdeflector 90 may be independently controlled. Each exhaust deflector 90may be adapted for movement, e.g., by extending and retracting exhaustdeflector 90, to and from a location aft, or downstream of, fixed nozzle30, whereby a thrust vector direction of gas turbine engine 20 may becontrolled (see, e.g., FIGS. 5A-D). Such movement of exhaust deflectors90 for thrust vector control may typically comprise translationalmotion. In some embodiments of the invention, movement of exhaustdeflectors 90 for thrust vector control may include a combination ofrotational and translational motion.

FIGS. 4A-C each show a configuration of a deflection unit 60 for athrust vector control apparatus 40, according to the invention.Deflection unit 60 may comprise an actuator 70 coupled to an exhaustdeflector 90 via a linkage unit 80. Linkage unit 80 may comprise one ormore segments and one or more articulation units. As an example, linkageunit 80 may include first and second segments 82 a, 82 b, and first andsecond articulation units 84 a, 84 b. First and second segments 82 a, 82b and exhaust deflector 90 may each be of fixed or variable lengths. Forexample, one or both of first and second segments 82 a, 82 b may beextendible (see, FIG. 4C). Articulation units 84 a, 84 b may each definean articulation point, or pivot point, for deflection unit 60, andarticulation units 84 a, 84 b may comprise one or more hinges, and thelike. Other numbers and arrangements of segments and articulation unitsare possible under the invention. Movement of exhaust deflector 90 andlinkage unit 80 may be actuated via actuator 70 by various mechanismswell known in the art. Other configurations for independentlycontrolling movement of exhaust deflector(s) 90 with respect to fixednozzle 30 are also within the scope of the invention.

FIG. 4A shows deflection unit 60 in a retracted or partially retractedconfiguration. In such a retracted or partially retracted configuration,exhaust deflector 90 may not extend downstream of fixed nozzle exit 32;and accordingly, exhaust deflector 90 may not influence a default orfirst thrust vector direction of fixed nozzle 30, wherein the firstthrust vector direction may be axial or substantially axial (see, e.g.,FIG. 5A).

FIG. 4B shows deflection unit 60 in an extended or partially extendedconfiguration, such that exhaust deflector 90 may extend downstream offixed nozzle exit 32 (see, e.g., FIG. 5B-D). FIG. 4C shows aconfiguration of deflection unit 60 in which first segment 82 a isextended from actuator 70. It will be readily apparent to the skilledartisan that other configurations of deflection unit 60 are possible,for example, by a combination of extension and articulation of one ormore of first and second segments 82 a, 82 b, in order to provide alarge variety of positions of exhaust deflector 90 with respect to fixednozzle exit 32 (see, e.g., FIG. 5C). Exhaust deflectors 90, which may beadapted for deflecting exhaust gas discharged from nozzle 30, may beplanar or non-planar.

FIG. 5A is a side view schematic representation of a thrust vectorcontrol system 100 showing a first exhaust deflector 90 a and a secondexhaust deflector 90 b in relation to fixed nozzle 30. Thrust vectorcontrol system 100 may include a first actuator 70 a coupled to firstexhaust deflector 90 a via a first linkage unit 80 a, and a secondactuator 70 b coupled to second exhaust deflector 90 b via a secondlinkage unit 80 b. A vehicle structure 12 may at least partially enclosenozzle 30. Structure 12 may comprise, for example, an engine nacelle oran aircraft skin. First and second actuators 70 a, 70 b and/or first andsecond linkage units 80 a, 80 b may be affixed to vehicle structure 12.

In FIG. 5A, first and second exhaust deflectors 90 a, 90 b are shown ina retracted position, e.g., first and second exhaust deflectors 90 a, 90b are not downstream of fixed nozzle exit 32, such that the effectivethroat area is maximal and a first thrust vector direction 120 a issubstantially parallel to nozzle axis 31. For example, when first andsecond exhaust deflectors 90 a, 90 b are in the configuration shown inFIG. 5A, first thrust vector direction 120 a may deviate from thedirection of nozzle axis 31 by 5° or less, and usually first thrustvector direction 120 a may deviate from the direction of nozzle axis 31by 2° or less.

FIG. 5B is a side view schematic representation of a thrust vectorcontrol system having both first exhaust deflector 90 a and secondexhaust deflector 90 b in an extended or partially extended position,according to the invention. Although both first and second exhaustdeflectors 90 a, 90 b are shown in FIG. 5B as downstream of fixed nozzleexit 32, movement of each of first and second exhaust deflectors 90 a,90 b may be independently controlled (see, e.g., FIGS. 5C-D). Theconfiguration of first and second exhaust deflectors 90 a, 90 b shown inFIG. 5B effectively decreases throat area as compared with FIG. 5A,although the configuration of FIG. 5B may maintain first thrust vectordirection 120 a at least substantially as for FIG. 5A.

FIG. 5C is a side view schematic representation of thrust vector controlsystem 100 in which first exhaust deflector 90 a is extended to alocation downstream of fixed nozzle exit 32, while second exhaustdeflector 90 b is not downstream of fixed nozzle exit 32, such that onlyfirst exhaust deflector 90 a is in a position to deflect exhaust gasdischarged from nozzle 30. The configuration of FIG. 5C provides asecond thrust vector direction indicated as 120 b, wherein second thrustvector direction 120 b defines a thrust vector angle, α with respect tonozzle axis 31. Typically, thrust vector angle, α may be in the range offrom about 0° to 30°, usually from about 0° to 20°, and often from about0° to 15°.

FIG. 5D is a side view schematic representation of thrust vector controlsystem 100 in which second exhaust deflector 90 b is extended to alocation downstream of fixed nozzle exit 32, while first exhaustdeflector 90 a is not downstream of fixed nozzle exit 32, such that onlysecond exhaust deflector 90 a is in a position to deflect exhaust gasdischarged from nozzle 30. The configuration of FIG. 5D may provide athird thrust vector direction, indicated as 120 c, which subtends thrustvector angle, α to nozzle axis 31. It is to be understood thatintermediate positions, between fully extended and fully retracted, arewithin the scope of the invention for each exhaust deflector, e.g.,first exhaust deflector 90 a, and second exhaust deflector 90 b. Forexample, with reference to FIG. 5D, first exhaust deflector 90 a may bepartially extended, to a position intermediate between the retractedposition of FIG. 5A and the extended position of FIG. 5B. Such partialextension of first exhaust deflector 90 a may serve to decrease nozzlethroat area, e.g., as compared with FIG. 5D. At the same time, suchpartial extension of first exhaust deflector 90 a may serve to decreasethrust vector angle, α, as compared with that shown in FIG. 5D. Thus,the present invention may allow simultaneous control over both nozzlethroat area and thrust vector direction. It is to be understood that theinvention is not limited to the configurations, or actuation mechanisms,shown in FIGS. 5A-D, but instead other configurations and actuationmechanisms for thrust vector control are also within the scope of theinvention. Fixed nozzle exit 32 may be circular or substantiallycircular. Alternatively, fixed nozzle exit 32 may be substantiallyflattened in one or more planes.

FIG. 6 is a lateral cross-sectional view schematically representing aflight vehicle 10 having a vehicle skin 14, and indicating a pitchplane, PP and a yaw plane, YP of flight vehicle 10. Thrust vectordirections 120 b, 120 c of FIGS. 5C and 5D may be in the pitch plane, PPor the yaw plane, YP. When thrust vector directions 120 b, 120 c are inthe yaw plane of flight vehicle 10, the configurations of FIGS. 5C and5D may give a tail-up force and a tail-down force, respectively.Alternatively, when thrust vector directions 120 b, 120 c are in thepitch plane of flight vehicle 10, the configurations of FIGS. 5C and 5Dmay give a force to the left and a force to the right, respectively. Inalternative embodiments, exhaust deflectors 90, e.g., first and secondexhaust deflectors 90 a, 90 b, may be configured such that a thrustvector direction may be obtained in any plane (not shown) between thepitch plane and the yaw plane.

In some embodiments, thrust vector control system 100 may comprise asingle exhaust deflector 90, e.g., exhaust deflector 90 a. In otherembodiments, thrust vector control system 100 may comprise a pair ofexhaust deflector 90, e.g., first and second exhaust deflectors 90 a, 90b, wherein first and second exhaust deflectors 90 a, 90 b may bediametrically opposed. In still other embodiments (not shown), thrustvector control system 100 may comprise two pairs, or a total of four(4), exhaust deflectors 90, wherein each pair may be diametricallyopposed. It is to be understood that the invention is not limited to asingle exhaust deflector 90, nor to pairs of exhaust deflectors 90, andthat other numbers and arrangements of exhaust deflectors 90 are alsopossible under the invention. Typically, each of a plurality of suchexhaust deflectors 90 may be independently controlled during flight offlight vehicle 10 for efficient thrust vector control.

FIG. 7A schematically represents a method 200 for thrust vector controlof a flight vehicle, according to the invention, wherein step 202 mayinvolve passing exhaust gas from a fixed nozzle to provide a firstthrust vector having a first thrust vector direction. As a non-limitingexample, the fixed nozzle may be that of a propulsion gas turbine enginefor a flight vehicle. The fixed nozzle may have a fixed nozzle axis,which may define the first thrust vector direction. The first thrustvector direction may be parallel, or substantially parallel, to thefixed nozzle axis. The first thrust vector direction may provide axialthrust. The fixed nozzle may have a fixed nozzle exit. The fixed nozzleexit may define the most aft, or downstream, portion of the fixednozzle.

Step 204 may involve moving a first exhaust deflector with respect tothe fixed nozzle. The first exhaust deflector may be coupled, e.g., viaa linkage unit, to an actuator of a thrust vector control apparatus. Thethrust vector control apparatus may have elements, features, andcharacteristics as described hereinabove, e.g., with reference to FIGS.1-6. Step 204 may involve moving the first exhaust deflector to alocation downstream of the fixed nozzle exit. Step 204 may involvemoving the first exhaust deflector with respect to the fixed nozzle suchthat the first exhaust deflector deflects the flow path of the exhaustgas discharged from the fixed nozzle. Step 204 may thus provide a secondthrust vector having a second thrust vector direction. Step 204 may alsoinvolve moving the first exhaust deflector with respect to the fixednozzle exit such that the effective throat area is decreased.Accordingly, a magnitude of the second thrust vector may be changed.Thus, the present invention may allow for simultaneous control over boththrust vector magnitude and thrust vector direction.

Movement of the first exhaust deflector may be actuated by an actuatorunder the control of a controller, such as an automated flightcontroller (e.g., a FADEC). Movement of the first exhaust deflector withrespect to the fixed nozzle may be accomplished by articulation and/orextension of one or more segments of the linkage unit. Movement of thefirst exhaust deflector in step 204 may be in the form of translationalmotion only. Stated differently, movement of the first exhaust deflectormay be in a straight line so that every point on the first exhaustdeflector follows a parallel path and no rotation takes place. Inalternative embodiments of the invention, movement of the first exhaustdeflector in step 204 may include a combination of rotational andtranslational motion.

The second thrust vector direction may be at a thrust vector angle, a tothe nozzle axis. The thrust vector angle, α may typically be in therange of from about 0° to 30°, usually from about 0° to 20°, and oftenfrom about 0° to 15°. Depending on the orientation of the first exhaustdeflector, the second thrust vector direction may provide a tail-upforce, a tail-down force, a force to the left, or a force to the right.The first exhaust deflector may be configured with respect to the fixednozzle to provide the second thrust vector direction in the pitch plane,the yaw plane, or any plane between the pitch plane and the yaw plane.

Optional step 206 may involve retracting the first exhaust deflectorsuch that the first exhaust deflector is no longer downstream of thefixed nozzle exit. Step 206 may involve reverting from the second thrustvector direction to the first thrust vector direction. Alternatively,step 206 may involve partially retracting the first exhaust deflectorsuch that the second thrust vector direction may be varied, for example,according to the required flight control conditions for the flightvehicle.

Step 208 may involve moving a second exhaust deflector with respect tothe fixed nozzle. In some embodiments of the invention, moving thesecond exhaust deflector in step 208 may be in the form of translationalmotion alone, or may include a combination of both rotational andtranslational motion. Movement of the second exhaust deflector in step208 may substantially mirror movement of the first exhaust deflector asdescribed for step 204. For example, step 208 may involve moving thesecond exhaust deflector to a location downstream of the fixed nozzleexit such that the second exhaust deflector deflects the flow path ofthe exhaust gas discharged from the fixed nozzle. Movement of the secondexhaust deflector in step 208 to a location downstream of the fixednozzle exit may provide a third thrust vector direction.

In step 208, the second exhaust deflector may be moved to a locationdownstream of the fixed nozzle exit independently of the first exhaustdeflector. For example, the second exhaust deflector may be moved to alocation downstream of the fixed nozzle exit at a time when the firstexhaust deflector is partially or fully retracted, or the second exhaustdeflector may be moved to a location downstream of the fixed nozzle exitat a time when the first exhaust deflector is also located downstream ofthe fixed nozzle exit. In this way, the present invention may allowsimultaneous control over both nozzle throat area and thrust vectordirection.

Optional step 210 may involve at least partially retracting at least oneof the first and second exhaust deflectors to control the thrust vectordirection according to the required flight control conditions. Inadditional steps (not shown), one or more additional exhaust deflectorsmay be extended into, or retracted from, the exhaust flow path of thefixed nozzle to provide appropriate thrust vector control. Movement ofeach exhaust deflector may be independently controlled, for example, byan automated flight controller.

FIG. 7B schematically represents a method 300 for thrust vector controlof a flight vehicle, according to another embodiment of the invention,wherein step 302 may involve providing thrust vector control apparatusfor a flight vehicle. The thrust vector control apparatus provided instep 302 may have various elements, features, and characteristics asdescribed herein with respect to FIGS. 1-7A.

In some embodiments, step 302 may involve retrofitting a flight vehiclewith the thrust vector control apparatus. In alternative embodiments ofthe invention, the thrust vector control apparatus may be integral witha flight vehicle. The flight vehicle may be, for example, an aircraft,which may have a tail, such as a fixed-wing aircraft, or a rotorcraft; atailless flight vehicle; or an unmanned air vehicle (UAV), and the like.

Step 304 may involve passing exhaust gas from a fixed nozzle to providethrust having a first thrust vector direction which may be substantiallyaxial. Step 306 may involve independently moving one or more exhaustdeflectors with respect to the fixed nozzle to vary the thrust vectordirection. The thrust vector direction may be varied to provide a thrustvector angle, α to the fixed nozzle axis, typically in the range of fromabout 0° to 30°. Step 306 may involve translational motion of a singleexhaust deflector to a location downstream of the fixed nozzle.Alternatively, step 306 may involve translational motion of two or moreexhaust deflectors. In some embodiments of the invention, the two ormore exhaust deflectors may comprise at least one pair of diametricallyopposed exhaust deflectors.

The thrust vector control system of the present invention may providethrust vector control for gas turbine engines at all engine powersettings (e.g., take-off, cruise, idle), and may provide high thrustcoefficients, typically at least 95%, at pressure ratios equal to orless than 6.0. Accordingly, the present invention may provide smoothflight control with minimal or no unsteady, or separated, flow withinthe exhaust nozzle flow-path.

In addition to providing control of thrust vector direction, the presentinvention may also allow for control of nozzle throat area, includingsuch control of nozzle throat area independently of thrust vectordirection control.

Although the invention has been described primarily with respect tothrust vector control for a gas turbine engine, the present inventionmay also find applications in thrust vector control for rocket-propelledspace vehicles, missiles, and the like.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

1. A thrust vector control system, comprising: a fixed nozzle; and atleast one exhaust deflector adapted for movement to a locationdownstream of said fixed nozzle, wherein: said movement comprisestranslational motion, and said movement of each said exhaust deflectoris independently controllable.
 2. The thrust vector control system ofclaim 1, wherein: said fixed nozzle provides a first thrust vectordirection, said at least one exhaust deflector is capable of providing asecond thrust vector direction, and said second thrust vector directionis different from said first thrust vector direction.
 3. The thrustvector control system of claim 2, wherein: said fixed nozzle defines afixed nozzle axis, said first thrust vector direction is substantiallyparallel to said fixed nozzle axis, said second thrust vector directionis at a thrust vector angle, α to said fixed nozzle axis, and saidthrust vector angle is in the range of from about 0 to 30°.
 4. Thethrust vector control system of claim 1, wherein said exhaust deflectoris planar.
 5. The thrust vector control system of claim 1, wherein saidexhaust deflector is non-planar.
 6. The thrust vector control system ofclaim 1, wherein said exhaust deflector is disposed radially outwardfrom said fixed nozzle.
 7. The thrust vector control system of claim 1,further comprising at least one actuator coupled to said exhaustdeflector.
 8. The thrust vector control system of claim 7, furthercomprising at least one linkage unit, each said linkage unit adapted forcoupling each said actuator to each said exhaust deflector.
 9. Thethrust vector control system of claim 7, further comprising a controllerin communication with each said actuator, wherein said controller isadapted for independently controlling each said actuator.
 10. The thrustvector control system of claim 1, wherein said at least one exhaustdeflector comprises a pair of said exhaust deflectors.
 11. The thrustvector control system of claim 1, wherein said fixed nozzle is aconvergent nozzle.
 12. The thrust vector control system of claim 1,wherein said exhaust deflector is adapted for simultaneously controllingnozzle throat area and thrust vector direction.
 13. The thrust vectorcontrol system of claim 1, wherein said movement comprises rotationalmotion in combination with said translational motion.
 14. The thrustvector control system of claim 1, wherein said movement of said exhaustdeflector to said location downstream of said fixed nozzle is movementin a straight line so that every point on said exhaust deflector followsa parallel path and no rotation takes place.
 15. A thrust vector controlsystem, comprising: a fixed nozzle having a fixed nozzle axis and afixed nozzle exit, said fixed nozzle axis defining a first thrust vectordirection; and a single exhaust deflector adapted for movement to alocation downstream of said fixed nozzle exit to provide a second thrustvector direction.
 16. The thrust vector control system of claim 15,wherein: said second thrust vector direction is at a thrust vectorangle, α to said first thrust vector direction, said first thrust vectordirection is substantially parallel to said fixed nozzle axis, and saidthrust vector angle is from about 0° to 30°.
 17. The thrust vectorcontrol system of claim 15, further comprising at least one additionalexhaust deflector adapted for movement to a location downstream of saidfixed nozzle exit to provide a third thrust vector direction.
 18. Thethrust vector control system of claim 17, further comprising: at leastone actuator; and at least one linkage unit for coupling each saidactuator to each said exhaust deflector, wherein: each said linkage unitcomprises a plurality of segments, and at least one of said segments isarticulated.
 19. A thrust vector control system, comprising: a fixednozzle for a gas turbine engine, said fixed nozzle having a fixed nozzleexit; and a thrust vector control apparatus including at least oneexhaust deflector, each said exhaust deflector adapted for independenttranslational motion to a location downstream of said fixed nozzle exit,wherein: said fixed nozzle provides a first thrust vector direction; andeach said exhaust deflector is adapted for converting said first thrustvector direction to a second thrust vector direction.
 20. The thrustvector control system of claim 19, wherein: said fixed nozzle is aconvergent nozzle having a fixed nozzle axis, said first thrust vectordirection is substantially parallel to said fixed nozzle axis, saidsecond thrust vector direction is at a thrust vector angle, α to saidfixed nozzle axis, and said thrust vector angle is from about 0° to 30°.21. The thrust vector control system of claim 20, wherein said thrustvector angle is from about 0° to 15°.
 22. A system, comprising: a gasturbine engine having a fixed nozzle for discharging exhaust gas; atleast one exhaust deflector, each said exhaust deflector independentlycapable of changing a first thrust vector of said gas turbine engine,each said exhaust deflector adapted for movement to a locationdownstream of said fixed nozzle; and an actuator adapted for actuatingsaid movement of each said exhaust deflector, wherein: said movement ofeach said exhaust deflector is independently controllable, and saidmovement of each said exhaust deflector comprises translational motion.23. The system of claim 22, wherein: said fixed nozzle has a fixednozzle axis and a nozzle exit, said fixed nozzle axis defines said firstthrust vector having a first thrust vector direction substantiallyparallel to said fixed nozzle axis, and said movement of each saidexhaust deflector to said location downstream of said fixed nozzleprovides a second thrust vector having a second thrust vector directionat a thrust vector angle, α to said fixed nozzle axis, wherein saidthrust vector angle is from about 0° to 30°.
 24. The system of claim 22,wherein: said gas turbine engine is a propulsion gas turbine engine forpropulsion of a flight vehicle, and said system has one (1), two (2), orfour (4) of said exhaust deflectors for each said gas turbine engine.25. The system of claim 24, wherein said system has two (2) said exhaustdeflectors for each said gas turbine engine.
 26. The system of claim 23,wherein said second thrust vector provides an upward force, a downwardforce, a force to the right, or a force to the left.
 27. The system ofclaim 22, further comprising: a linkage unit for coupling each saidexhaust deflector to said actuator, and a controller in communicationwith said actuator, wherein said controller is adapted for independentlycontrolling said movement of each said exhaust deflector.
 28. A thrustvector control apparatus, comprising: at least one deflection unit, eachsaid deflection unit including: an exhaust deflector adapted formovement to a location downstream of a fixed nozzle of a gas turbineengine, said fixed nozzle having a fixed nozzle axis, and an actuator incommunication with said exhaust deflector, said actuator for actuatingsaid movement, wherein: said fixed nozzle provides a first thrust vectordirection substantially parallel to said fixed nozzle axis, saidmovement of each said exhaust deflector to said location downstream ofsaid fixed nozzle comprises translational motion, and said movement ofeach said exhaust deflector to said location downstream of said fixednozzle provides a second thrust vector direction at a thrust vectorangle, α to said fixed nozzle axis.
 29. The thrust vector controlapparatus of claim 28, wherein: said deflection unit further includes alinkage unit for coupling said exhaust deflector unit to said actuator,and said linkage unit comprises at least one articulated segment. 30.The thrust vector control apparatus of claim 28, wherein said actuatoris adapted for control by a flight controller.
 31. The thrust vectorcontrol apparatus of claim 28, wherein said exhaust deflector comprisesat least one diametrically opposed pair of said exhaust deflectors. 32.The thrust vector control apparatus of claim 28, wherein said movementof said exhaust deflector to said location downstream of said fixednozzle is movement in a straight line so that every point on saidexhaust deflector follows a parallel path and no rotation takes place.33. The thrust vector control apparatus of claim 28, wherein saidmovement of said exhaust deflector to said location downstream of saidfixed nozzle comprises rotational motion in combination with saidtranslational motion.
 34. A flight vehicle, comprising: a gas turbineengine having a fixed nozzle; and a thrust vector control apparatus forcontrolling a thrust vector of said gas turbine engine, wherein: saidthrust vector control apparatus comprises at least one exhaustdeflector, each said exhaust deflector is independently controllable,and each said exhaust deflector is movable with respect to a fixednozzle exit of said fixed nozzle.
 35. The flight vehicle of claim 34,wherein: said fixed nozzle defines a fixed nozzle axis, said fixednozzle is adapted for discharging an exhaust gas in a substantiallyaxial direction to provide a first thrust vector having a first thrustvector direction, each said exhaust deflector is adapted fortranslational motion to a location downstream of said fixed nozzle exit,each said exhaust deflector is adapted for providing a second thrustvector having a second thrust vector direction, and said second thrustvector is different from said first thrust vector direction.
 36. Theflight vehicle of claim 34, wherein each said exhaust deflector isadapted for providing nozzle throat area control simultaneously withproviding said second thrust vector direction.
 37. The flight vehicle ofclaim 35, wherein: said second thrust vector direction defines a thrustvector angle, a to said fixed nozzle axis, and said thrust vector angleis from about 0° to 30°.
 38. The flight vehicle of claim 35, whereinsaid second thrust vector direction is in the pitch plane of said flightvehicle or the yaw plane of said flight vehicle.
 39. The flight vehicleof claim 35, wherein said second thrust vector direction is in any planebetween the pitch plane and the yaw plane of said flight vehicle. 40.The flight vehicle of claim 34, further comprising a flight controllerin communication with said thrust vector control apparatus forindependently controlling movement of said at least one exhaustdeflector.
 41. The flight vehicle of claim 34, comprising a rotorcraftor a fixed-wing aircraft.
 42. The flight vehicle of claim 34, comprisingan unmanned air vehicle.
 43. A method for thrust vector control of aflight vehicle, comprising: a) passing exhaust gas from a fixed nozzleof a gas turbine engine, said fixed nozzle having a fixed nozzle axisdefining a first thrust vector direction; and b) moving at least oneexhaust deflector to a location downstream of said fixed nozzle toprovide a second thrust vector direction.
 44. The method of claim 43,wherein: said first thrust vector direction is substantially parallel tosaid fixed nozzle axis, and said second thrust vector direction is at athrust vector angle, α to said fixed nozzle axis.
 45. The method ofclaim 44, wherein said thrust vector angle is from about 0° to 30°. 46.The method of claim 43, wherein said step a) provides a first thrustvector, and said step b) provides a second thrust vector, wherein saidsecond thrust vector provides a tail-up force to said flight vehicle, ora tail-down force to said flight vehicle.
 47. The method of claim 43,wherein said step a) provides a first thrust vector, and said step b)provides a second thrust vector, wherein said second thrust vectorprovides a force to the left to said flight vehicle, or a force to theright to said flight vehicle.
 48. The method of claim 43, wherein saidat least one exhaust deflector comprises a first exhaust deflector and asecond exhaust deflector, wherein said first exhaust deflector and saidsecond exhaust deflector are independently movable with respect to saidfixed nozzle.
 49. The method of claim 48, wherein said first exhaustdeflector and said second exhaust deflector are disposed on opposingsides of said fixed nozzle.
 50. The method of claim 43, wherein said atleast one exhaust deflector comprises a first exhaust deflector, and themethod further comprises: c) retracting said first exhaust deflectorsuch that said first exhaust deflector is not disposed downstream ofsaid fixed nozzle; and d) moving a second exhaust deflector such thatsaid second exhaust deflector is disposed downstream of said fixednozzle to provide a third thrust vector direction.
 51. The method ofclaim 43, wherein said at least one exhaust deflector comprises a firstexhaust deflector, and the method further comprises: e) moving a secondexhaust deflector such that said second exhaust deflector is disposeddownstream of said fixed nozzle, wherein said step a) provides a firstthrust vector magnitude, and said steps b) and e) provide a secondthrust vector magnitude.
 52. The method of claim 51, further comprising:f) retracting at least one of said first exhaust deflector and saidsecond exhaust deflector.
 53. The method of claim 43, wherein said stepb) comprises moving a single one of said at least one exhaust deflector.54. The method of claim 43, wherein said step b) comprises translationalmotion of said at least one exhaust deflector.
 55. The method of claim43, wherein said step b) comprises providing nozzle throat area controlsimultaneously with providing said second thrust vector direction.
 56. Amethod for thrust vector control of a flight vehicle, comprising: a)providing a thrust vector control apparatus for said flight vehicle,wherein said flight vehicle includes a gas turbine engine having a fixednozzle, said fixed nozzle having a fixed nozzle axis defining a firstthrust vector direction substantially parallel to said fixed nozzleaxis, and wherein said thrust vector control apparatus comprises atleast one exhaust deflector; b) passing exhaust gas from said fixednozzle; and c) moving said exhaust deflector with respect to said fixednozzle to provide a second thrust vector angle, α to said fixed nozzleaxis, wherein said step c) comprises translational motion of said atleast one exhaust deflector to a location downstream of said fixednozzle.
 57. The method of claim 56, wherein said step a) comprisesretrofitting said flight vehicle with said thrust vector controlapparatus.
 58. The method of claim 56, wherein said thrust vectorcontrol apparatus provided in said step a) is integral with said flightvehicle.
 59. The method of claim 56, wherein said step c) comprisesmoving said exhaust deflector in a straight line so that every point onsaid exhaust deflector follows a parallel path and no rotation takesplace.
 60. The method of claim 56, wherein said step c) comprises movingsaid exhaust deflector by a combination of rotational motion with saidtranslational motion.
 61. The method of claim 56, wherein said step c)comprises moving a single one of said exhaust deflector downstream ofsaid fixed nozzle.